Robert Nozick is probably most familiar to readers of this column as a libertarian political philosopher, but this week I’d like to look at another issue, relevant not only to libertarians but to anyone interested in moral and political thought, which he discusses in his last book, Invariances (Harvard, 2001.) This is whether our beliefs about these subjects are objectively true or merely the expression of preferences. If we say, e.g., that people own themselves, is this something that is true or is it just a preference that we have?
Nozick doesn’t think it’s true. Not that he thinks it’s false—i.e., that it’s true that people don’t own themselves. Rather Nozick questions whether ethical truths exist at all.
How can ethical statements be true, if truth consists in correspondence to the facts? Are there special kinds of facts, ethical ones, and if so, by what route do we discover them? … The history of philosophy is abundant with unsuccessful attempts to establish a firm basis for ethical truths. Inductively, we infer that the task is unpromising.
But don’t our considered moral judgments put us in touch with moral facts? Nozick finds no basis in evolutionary theory to account for this claimed grasp of moral facts. Suppose he is right that we cannot explain by use of Darwinian evolution how we can grasp ethical truth. Why should we take this as a decisive reason to abandon the claim that we know such truths? Perhaps we instead have grounds to doubt that Darwinian processes account for all our knowledge.
We might press the point further. It is hard to explain through evolution how we know any necessary truths. Does this give us reason to abandon necessary truth? If not, why should we toss moral truths overboard on Darwinian grounds?
Nozick fully anticipates this response, but his answer I find astonishing. He does propose abandoning necessary truth, in large part because by evolution he cannot account for how we might attain such knowledge. Why he accords evolutionary considerations such enormous weight escapes me.
But my skepticism is not an argument, and Nozick’s intricately elaborated alternative to ethical truth merits attention. Once again, Darwinian evolution exerts decisive weight. Nozick endeavors to determine the evolutionary function of ethics. Why has natural selection endowed us with the capacity to make moral judgments? He plausibly suggests that cooperative behavior in some circumstances increases “inclusive fitness.”
Again, suppose Nozick is right. Why does this matter for ethics? As always, he has considered the objection:
Derek Parfit … asks the pertinent question of what difference is made by something’s being the function of ethics. Many things have bad functions (war, slavery, etc.). And even when the function is a good one, as evaluated by the standards instilled to go with cooperation, is normative force added by saying that this good effect of ethical principles (namely, enhancing mutual cooperation) also is the function of ethics?
Nozick’s response brings out a key feature of the book. Ethical rules not only have a function but also exhibit certain properties that enable them to carry out this function effectively. One of these has decisive importance to our author. “Objective ethical truths … are held to involve a certain symmetry or invariance…. The Golden Rule mandates doing unto others as you would have others do unto you.” As Nozick sees matters, invariance under transformation is the mark of truth. Once we combine function with invariance, in a vastly more complicated way than I can here explain, we arrive at a close substitute for objective truth.
Nozick is right that cooperative behavior of various sorts might have benefited our ancestors. On evolutionary grounds, though, wouldn’t a tightly knit group able to prey on others also have enjoyed a selective advantage? So, at any rate, Sir Arthur Keith long ago maintained in A New Theory of Human Evolution (1948). Why don’t rules that mandate aggression against strangers also qualify as part of Nozick’s close substitute for objective ethics? Nozick might counter with the claim that such rules do not admit of generalization in the way that he holds is required for his version of objectivity. But this remains to be shown. Generalization need not bring us to “love to all people, perhaps all living creatures,” much less to “being … vessel[s] and vehicle[s] of Light,” the two highest levels of Nozick’s ethics (it can equally well eventuate in a far more Nietzschean outcome. It all depends on the initial principle from which you generalize.
Faced with Nozick’s convoluted analysis, which he himself worries has too many epicycles, I feel like asking why he can’t just see that values are really present in the world. Why need one abandon what is self-evident in favor of a speculative substitute for genuinely objective values?
Here we reach bedrock. Fundamental to Invariances is Nozick’s distrust of claims of direct knowledge of the nonempirical. We do not “just know” that people have rights any more than we directly see that both sides of a contradiction cannot at the same time be true. Once again, evolution forbids it. “Such debates [about necessary truth] would be avoided if we possessed a faculty of reason that could directly assess the possibility of general statements and of their denials…. However, we do not appear to have such a faculty, and it is implausible that evolutionary processes would instill that within us.”
But doesn’t this create a problem for Nozick’s libertarianism? He famously began Anarchy, State, and Utopia by telling us “individuals have rights.” Aren’t such absolute claims ruled by Nozick’s newly installed divinity, Evolution? He can at most say that an evolutionary story makes it somewhat plausible that one can hold, as a personal ideal, that people cannot be coerced in ways that violate their rights. This hardly seems worth writing home about.
Nozick’s rejoinder is obvious. No doubt it would be convenient for libertarians if we could claim our doctrine to be objectively true; but fairness to the facts requires that we abandon this claim. And to support his denial that we directly grasp necessary truth, Nozick deploys an intriguing argument: To claim something is necessarily true is to say that it is true in all possible worlds: it cannot be otherwise. Isn’t this an extraordinary claim to make? To claim, by contrast, that something is possible is a much more modest assertion. “It is easier to think of possibilities than of necessities, easier to know that something is possible than that it is necessary.” Don’t exponents of necessary knowledge mistakenly seek to limit the imagination? Who are we to say that something must be so?
But if something is possible, then nothing in any possible world renders it impossible. Isn’t claiming that this is true as radical a claim as the one Nozick would deny to us? Oddly, Nozick elsewhere makes an analogous claim: “A theory can appear consistent and transparent … yet still harbor contradictions…. Not everything that looks consistent really is possible.” But he does not note this observation’s bearing on his earlier contention. Nozick’s argument leaves claims to necessary truth undamaged, unless he also wishes to throw into question our knowledge of possibility.
Further, why do those who claim direct access to real values have to say that propositions about value are necessary? Why isn’t it enough to assert that the value propositions are true in the actual world, and in “nearby” possible worlds? To me, the “moral” of Nozick’s account is that we should be reluctant to throw away what seems manifestly true because of difficulties in reconciling this with evolution.